WFA 4.0 workflow designer is destroying workflows

When reordering user inputs then some inputs get lost. The workflow cannot be started because of a lost reference to an user input. Further user inputs cannot be added to this workflow. The workflow is destroyed.

Details:

This is my user input tab in workflow designer:

Then the order of two user inputs is changed:

Now changing to the "constants" tab and back again:

Userinput "_SvmRole" is gone. When saving the workflow in this state it cannot be used any more: